Starting-crank safety device for motor-vehicles.



L. c. SHARP.

STARTING CRANK SAFETY DEVICE FOR MOTOR VEHlCLES. 7

APPLICATION FILED 1AN.'21, I911.

\ 1,288,708.. Patent-ed Dec. 24, 1918.

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LEE 0. SHARP, OF PLATTSMOUTH, NEBRASKA.

STARTINGVCRANK SAFETY DEVICE FOR MOTOR-VEHICLES.

Specification of Letters Patent.

Patented Dec. 24:, 1918.

Application filed January 27, 1917. Serial No. 145,015.

To all whom it may concern:

Be it known that I, LEE C. SHARP, a citizen of the United States, and aresident of Plattsmouth, in the county of Cass and State of Nebraska,have invented certain new and 'useful Improvements in Starting-CrankSafety Devices for Motor-Vehicles, of which the following is aspecification.

My invention relates to motor vehicles propelled by internal combustionengines, and particularly to starting-cranks for such engines. It is theobject of my invention to provide a simple, inexpensive andeasilyinstalled safety-device for preventing reverse movement of thestarting-crank due to backfiring or premature ignition of a charge whenstarting a motor-vehicle engine by hand. Backfiring of internalcombustion engines during the starting thereof occurs very frequentlyand usually results from premature ignition, due to incorrect adjustmentor too great advance of the ignition-timing devices, although alsoresulting occasionally from other causes such that the improperoperation can not be prevented even by the exercise of special care onthe part of the operator. When starting an engine by hand-crankingthereof, backfiring often results in serious injury to the personholding the crank, the latter being forcibly pulled from the hand andmaking one or more reverse revolutions during which the person may bestruck thereby, and frequently bones of the hand, arm or jaw are broken,and even deaths are sometimes caused by this means. My invention provides a positive and reliable means for the prevention of suchaccidents.

In the accompanying drawings Figure 1 is a front elevation of devicesembodying my invention, parts thereof being in section on the plane ofthe line 11 of Fig. 2, and Fig. 2 is a longitudinal vertical section ofthe same on the line 2-2 of Fig. 1.

The illustrated embodiment of my invention is especially designed foruse on the well-known Ford motor-vehicles, and there are shown in thedrawings the related parts of such a vehicle necessary to illustrate theconnection of my safety device there with. Thus, there is shown in Fig.2 the front end-portion of the engine crank-case,

said part 3 having secured thereto a bearingmember 4: which rests in aseat or pillo wblock 5, and the latter resting upon the central portionof the front cross-member 6 of the vehicle-frame, as shown in Fig. 1.The radiator 7 is disposed above the cross-member 6, being in spacedrelation to the central part thereof, and said central part of thecrossmember rests upon the front spring 8, being secured thereto bymeans of U-bolts 9 of which the upper ends pass through projecting lugs10 on the base-portion of the pillow-block 5. The bearing-member 4 has alongitudinal bore or opening in which there is permanently secured asleeve 11, the latter being in axial alinement with the enginecrank-shaft 12. The front end-portion of the crank-shaft has the usualcross-pin 13 for engagement by the head of the startingcrank. All of theforegoing parts are of the construction and arrangement usually found invehicles of the class mentioned. The head 14: of the starting-crank isalso of the usual form and comprises a cup-shaped body, adapted to passloosely over the end of the crank-shaft 12, and having in the endthereof helically-extending notches forming ratchet-like teeth forengagement with the pin 13.

The head 14c is carried on the rear end of a shaft 15 which fitsrevolubly and slidably in the bore of the sleeve ll,the head beingsecured to the shaft by means of a pin 16. The

front end-portion of the shaft 16 projects be yond the bearing thereforin the sleeve 11 and carries the hand-crank 17 of which the hub-portion18 is secured to the shaft by a pin 19. On the rear end of the hub 18and integral therewith is a ratchet-wheel 20 of which the end iscounterbored to receive a portion of a coil spring 21 disposed aroundthe shaft in front of the bearing-sleeve 11. Said spring 21 holds theshaft 15 normally in the position shown in Fig. 2, at which the end ofthe head 14: engages the rear end of the sleeve 11, but by compressionof the spring the shaft may be moved rearwardly to a position at whichthe head will pass over the end of the crank-shaft 12 and engage thecross-pin 18 thereon. When the shaft is in the latter position, theratchet wheel 20 is in proximity to the front end of the bearing-member4, and most of the spring 21 lies within the counterbore of the end ofthe ratchet-wheel. In front of the frame cross-member 6 there isdisposed-a stop-supporting bracket having laterally extending lugs 22which rest upon the lugs 10 of the pillow-block 5, the ends of the U-bolts 9 passing through said lugs 22, and the latter being clampedagainst the lugs 10 by nuts 23 screwed on the threaded upper portions'of the U-bolts. Said stop-supporting bracket has an annular centralportion 24 disposed concentrically with the shaft 15, and at the lowerside of said annular portion there is a tubular depending socket 25.Within the bore of the socket 25 a cylindrical pawl-stem 26 fitsslidably, the upper end of said stem having at one side a fiat face 27adapted to engage the radial portions of the teeth on the ratchet-wheel20. A pin 28 extends horizontally through the stem 26, the ends of saidpin fitting slidably in vertical slots 29 in the sides of the socket 25.The lower end of the stem 26 has a cylindrical recess therein, and insaid recess is disposed the upper portion of a coil spring 30 of whichthe lower end rests on the bottom of the socket 25. At the upper end ofthe recess in the stem there is a threaded opening for receiving the endof a screw 31, which passes down through the spring and the bottom ofthe socket, having at its lower end a head between which and the bottomof the socket are disposed washers 32 and 33. The washer 33 is ofleather or like yieldable material, and forms a cushioning stop forlimiting upward movement of the screw and stem 26. The length of thestop-screw 31 is so proportioned that at the limit of upward movement ofthe pawlstem 26 the upper end thereof will be in approximately therelation to the ratchetwheel 20 shown in Fig. 1, in which there is aslight clearance between the end of the stem and the adjacent tangentialtooth-face of the wheel. Thus, when the shaft 15 is in the forwardposition shown in Fig. 2, the pawl-stem cannot move up far enough tointerfere with the rearward movement of the ratchet-wheel, if the latterbe turned so that the pawl-stem is alined with one of the notchesbetween the ratchet-teeth. It will be noted that the relation of theparts longitudinally of the shaft-axis is such that the wheel 20 andpawl-stem 26 are in en gaging relation to each other whenever the head14: is in position to engage the crosspin 13 of the engine crank-shaft,and that when the shaft 15 is moved forwardly the ratchet-wheel 20 isdisengaged from the pawl-stem subsequently to the disengagement of thehead 14 from the cross-pin 13.

When starting the engine, the hand-crank is manipulated in the usualmanner, the same being pushed rearwardly far enough to engage thecrank-shaft 12 and the latter being turned thereby as required to causethe suction, compression and ignition of one or more charges in theengine cylinders. The

engagement of the pawl-stem 26 with the ratchet-wheel 20 effectivelyprevents movement of the starting-crank except in the normal directionof rotation of the engineshaft, and, should the engine backfire duringthe cranking thereof, the force of the impulse will be received by thestem 26 and the stop-support carrying the same, instead of beingpermitted to cause reverse movement of the crank 17. If it is desired tostart the engine by making only partial turns of the starting-crank,instead of spinning or continuous turning thereof, the ma- 7 reversemovement of the crank. It may be noted that the parts are preferably soproportioned that the strength of the stop-pawl 26 is greater than thatof the pins 16 and 19, sothat should the force of an impulse due tobackfiring be great enough to cause breakage of any of the parts, one ofsaid pins 16 or 19 will be sheared ofi instead of any other parts beingbroken. Such breakage would, of course, only occur under extremelyadverse conditions, and the damage would be the minimum possible,involving merely the replacement of the sheared pin to restore themechanism to its original condition.

Now, having described my invention, what I claim and desire to secure byLetters Patent is:

In a mechanism of the class described, the combination with anengine-shaft, a starting-shaft alined therewith, a bearing for thelatter shaft in which the same is rotatable and longitudinally slidable,a toothed head on the starting-shaft adjacent to the engineshaft, meanson the latter with which said toothed head is engaged by movement of thestarting-shaft longitudinally toward the same, and a hand-crank carriedby the start- 7 V as to be in operative relation to said stop when thetoothed head is engaged with the engine-shaft, means for pressing saidstop yieldably toward. the shaft-axis, and means for preventing movementof the stop toward said shaft-axis beyond the notches of the Copies ofthis patent may be obtained for wheel, said stop and notched wheel beingengageable to prevent rotation of the starting-shaft except in thedirection of normal rotation of the engine-shaft.

L. G. SHARP.

five cents each, by addressing the Commissioner of Patents, Weshinn, D.43.

